We didn’t know you were in trouble at that time; _______ we would have given you a hand.
Plants grow well ______ there is plenty of water and sunshine.
—Did you write to Grace last summer? —No, but I'll ______ her over Christmas vacation.
In summer people usually stay up late outside, ______ the cool air.
The foreiger knows little about ______ is called "Hope Project" in China.
He was born ____ a very cold night _____ December.